First shot(s) variance in Norc M305

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bazza

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Still early days with my M305, but it would appear that it takes a couple of shots to settle down the rifle. I'm still shooting with open sights, but after the first three shot group (usually right at or just under two inches at 50m) the next few series of three shot groups tighten right up to just over the 1 inch mark . Having said that, I had a Sako bolt action 7mm08 that took about a dozen rounds from a clean barrel before the groups tightened up to MOA. Any tips on eliminating first shot variance in the M305? Or is this normal for the M14 action?
 
I took mine out and just shot it, ran a patch between 5 rounds and after a hundred or so the difference was noticeable. My buddy did the same thing, sans cleaning and his shoots just as good.
 
Maybe quit cleaning the bore? Mine's pretty consistant first shot through to around 10, then heat starts to set in and mess with the point of impact. Do you have some grease between the barrel band and stock ferule? Also, don't pressure the forestock too much by leaning into a rest, it may influence the barrel as it "beds" at that stock to ferule where it should be greased.
 
yup, greased between the band/ferule, I'm picking the variance is due to the spotless clean barrel. While I always run a dry patch patch through and swab the chamber, I'm picking there was still some Slip 2000 left in the bbl. Can't wait to check out the performance of the Black Arrow ORSG tonight....
 
currently shooting Hornady 168gr A-Max and Hornady 150gr SST, looks like the 168 will win out. I'll try only running one patch or so between shooting sessions and see how that goes. Still early days as I need to get 200 odd rounds through to establish reliability and see what may break or become loose.
 
I'm by no means an expert, but being as its a new rifle there will be some break in time. Tightening the gas system, muzzle break and operation Rod, *updating to a USGI spring and Spring Guide* could make some strides on your repeatability.

If you remove the barrel assembly and action from the stock, turn it over and look at the op rod, cycle the action and see if there is much play in the system and if it contacts the same place on the piston each time it cycles. This could cause some variation of accuracy. You could also have your brass Mic'ed to see your chamber size.

As I have been told by experts, the m305 is a battle rifle, clean it after a few days of use and Oil it after your done for the day. Keep the bolt and op rod assembly greased.

Just a few ideas.
 
bazza said:
...after the first three shot group ...the next few series of three shot groups tighten right up
Click to expand...

The first group after what? If you mean the first group of the day, and you are one of those weird people who actually cleans guns, you should know that the US Army MTU policy was to never disassemble the accurized M14s for cleaning. Taking them apart and re-assembling caused significant problems with wandering zeros.
 
Good point, the first group was after I (and I'm ashamed to admit it) cleaned & disassembled "The Beast". That explains it right there, while my Savage bolt action maintains no shift in POA after removing the stock, the M14 is a totally different animal! BTW, I'm loving this rifle!
 
Yep, a procedure change may help. The MTU taught to clean from the muzzle, with the bolt locked back and the rifle held in a vise upside down, so that solvents didn't drain through the gas port into the cylinder.
 
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